There are prior art methods for the preparation of polybutadienes wherein at least 90 percent of the butadiene units are present in the cis-1,4-configuration and a number of these methods utilize fluoride-bearing compounds with nickel compounds and aluminum compounds as the catalyst system. However, in order to make a stereoregular polymer that is suitable for plastics grade usage, that is, can be used as the impact-imparting component of impact grades of polystyrene, it is important that the polymers have a minimal gel content in addition to being produced with a fairly rapid rate of polymerization since it is economically unfeasible to have a very long polymerization time in a commercial operation.